Concentration circuit for simplex printers



May 5, 1931. H. w. BRAKE ET Al.

CONCENTRATION CIRCUIT FOR SIMPLEX PRINTRS Filed Jan.

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Patented May 5, 1931 HERBERT W. BRAKE, OF EAST ORANGE, NEW JERSEY, AND WiLLiAi/L B. BLANEON, OE

BROOKLYN, NEW YORK, YAssierNoRs To THE WESTERN UNION TELEGRAPH corvi- EANY, or NEW YORK, N. Y., A ooRroRAfrioN or NEW YORK v CONCENTRATON CRCUIT FR SIMFLEX PRENTERS Appiicanon inea January ai, 192e. serieu No. 336,617.

This invention relates to a Vcircuit arrangement for handling traffic to and from a number of telegraph printers of the start and stop type; suchras the Well-*known simplex printers.

An object of the invention is to devise a circuit arrangement whereby a number of simplex printer lines fromY outlying branch stations may be terminated at a central station, vand the traflic of said vlines handled by Va smaller number of simplex printers at the central station.; v Further objects of our invention will be apparent from the detailed description Which follows. y

Our invention is illustrated in the accompanying drawing in Which, for the sake of convenience, the circuit arrangement is illustrated for only one branch office, and only one simplex printer is shown at the central ottico.y

Referring to the dra-Wing, the equipment at each branch station comprises a simplex printer SP', a key switch K, and a signal relay G. The branch station is connected by a line L to the central station. Viith the key K in lthe position illustrated, the line L is grounded through the signal relay Gr, andV in the other position of the key, the relay G is disconnected and the line L is grounded.

through the simplex printer. Operation of key K also completes the energizing circuit of the printer operating motOr'M.

At the central station, line LV is connected through Winding 5 of relay C to line plugs 1, 2, 3 and 1, rigidly located in front of the respective operators It should bevv understood that While only four line plugs are shown,A there may be more of these plugs connected in multiple With these four, the number of line plugs depending on the number of operators to which it is desired to make this line accessible.Y The tongue of relay C is grounded through a source of current 6.

VindinsgV`V or" relay C" is connected from the Contact of relay C through Winding 8 of relay B to ground through contacts on interruptor R..` rllie left-hand tongue ot' relay B is connected through Winding 9 of said relay to ground through the contacts 0i of interrupterR; and the contact cooperating With this tongue is grounded through a source oi" current 19. The inner right-hand Vtongue oi relay B' is connected to ground through airesistance and a busy lamp 10. The vouter right-hand tongue of relay B is connected to the left-hand tongue of relay A. The 'right-hand tongue of relay A is connectedto. ground, and the back contact of this tongue is connected to ground through an answer lamp 11 and a source of current 12. One sid-e of the operating AWinding'oi1 relay A connected to ground through a signal battery SB, and also to the back contact of the left-hand tongue of relay A. The

l Lace-327 other terminal of the operating coil of relav A. is connected to the movable Contact 13 di relay B. and to the` back contact cooperating With the outer right-hand tongue of relay B. rlhe line L is connected to the stationary contact cooperating with movable contact 13 of relay B. That. part of thecircuit described inathe foregoing paragrapli be. called a concentration unit circuit.

The operators cord circuit comprises the circuit arrangement'interconnecting the jack J with relays D, E and F and with the sii-nplex printer SP2. The tip contact in the jack J is connected to the right-hand tongue of relay E, and the back Contact 'cooperating With this tongue is `connected .through Winding 151. of relay D to the plate element of a two-electrode vacuum. tube VT; the ilament or" the tube beingV grounded. One of the` extra contacts on jack J is connected -to ground. and the other cooperating `extra contact is connected to the tongue of relay D. lWinding 15 of relayD andthe windings of relaysE and F are connected in seriesl in a circuit eX-Y tending r'orn the contact of relay D to cooperating with this tongue is connected through a busy lamp 17, and a source of current 1778, to ground. The contact of relay F Vvenientto her.

is included in the motor operating circuit of simplex printer SP2. The operating circuit for this printereXtends from the front contact of the right-hand tongue of relay E through the printer to ground through a source of operating current OB.

The operation is as follows:

lilith the printer at the branch otiice idle,

the circuits are as shown in the drawing, with plus battery normally impressed upon the line L through the operating winding of relay A from generator SB. lVhen the operator at the branch oftice wishes to transmit to the central otlice, she operates the key K to connect the printer to the line L and disconnects the signal relay G. She then presses a key on the simplex printer to momentarily interrupt the line. Such interruption deenergizes relay A, and the tongues of this relay fall back upon their back contacts, one energizing the answer lamp 11, andthe other short-circuiting the operating winding ot relay A through the outer right-hand tongue ot relay B. Upon the signal from the answer lamp 11, the operator at the central oflice plugs her ack J on to one of the line plugs 1 to 4, depending on which one is the most con- This connects the line L throughthe right-hand back contact of relay E, winding 14 of relay D, and vacuum tube VT to. ground. At the same time the extra contacts of jack J are closed and complete a circuit from ground through the tongue and coil. 15 of relay D, and through the coils of relays E and F. The current flowing through the vacuum tube VT from the line L is suflicient to operate relay D but is not suicient to operate relay C. Operation of relay E connects the printer SP2 to the line through its right-hand armature and disconnects vacuum tube VT. Operation of relay F completes the circuit to the operating motor of, the printer SP2. The increased line current from the generator CB, is sucient to operate relay C, which in turn energizes relay B through winding 8, and establishes a holding circuit for itself through winding 7. Op-

eration of relay B disconnects the signaling battery SB from the line, and establishes a holding circuit for itself through winding 9 and the contacts a on interruptor R. The holding circuit including coil 7 ot relay C and coil 8 of relay B, includes also contacts b of interruptor R. Operation of relay B removes the short circuit around the winding of relay A, and establishes an energizing circuit for busy lamp '10 from the signal battery SB through the winding of. relay A. Relay A operates to extinguish the answer lamp 11.Y

The circuit is now ready for message traffic.

Relay B will remain operated as long as the concentration unit operator has her cord circuit connected tothe line, as will now be explained: The circuit interruptor R is rotated at an approximate speed of one revolution in every two seconds, and the direction of rotation is such that the circuit including winding 9 of relay B is opened tirst. Relay C is locked up through winding 7, and relay B is locked up by both holding circuits through windings 8 and 9. When the interrupter R opens the hold-ingcircuit including winding 9, relay B remains operated by reason of the holdingcircuit including the winding 8. The circuit interrupter R now opens the holding circuit including winding 7 of relay C and winding 8 of relay B, but the latter relay remains operated through the holding circuit including winding 9, which has now been reestablished Relay C, however, is now under the control of its Winding 5 which is included in the line circuit. 1f during the time that contacts b of interrupter R are opened, a printer signal of current isr passing over the line circuit, relay C will remain in the operated condition due to its winding 5 being energized. On the other hand, if during the time contacts b of the interrupter are opened, a printer signal ot no current passes over the line, relay C will moveto its unoperated position, and will remain in this position until an impulse of line current again operates it.

Simplex printers operate on a seven unit code, consisting of elements oit current and no current in a line hatteried at one end and grounded at the distant end. The first unit of the code, known as the startingY impulse, is

always a period of no current. The next tive units are periods ot current and no current, in accordance with the Baudot code. The seventh unit is always a period of current, which will continue, until another letter is transmitted. These seven units constitute 3g cycles. The usual speed of operation is ajoproximately 22 cycles per second. t will therefore'be seen that the longest period of io currentwill occur when the code portion is entirely no current. This, added to the starting pulse, will give a total of 2X seconds or -232 seconds.

Since the longest period of no line current is seconds rela C 'i ill t 22 y v again opera e relay C and the opening of the locking cir-Y cuit through the winding 9 of relay B.

lil

The operators cord circuit is now in readiness for` use on another line. In the concentration unit circuit, however, relay C remains' operated until the circuit throughthe winding 7 oit relay C and the Winding 8 of relay B is opened by the interrupter. There nov7 being no line current through the Winding l5 of relay C, it Will remainunoperated. Re-

lay ll, however, is still operated duc to the locking circuit through its Winding 9, and will remain operated until the interrupter opens this locking circuit. Upon release of relay ll, Contact between movable contact arm 1B is made with the line L before contact is broken in the circuit to the lamp l0, thereby maintaining thc continuity Vof the circuit through relay A during the opening ot relay ll. TVhen the operator at the branch station shit'ts key K to the off-position, contact is completed from the line L through the signal relayV G before the circuit is broken from the line .li to the printers Sly, thereby preventing the line circuit from being momentarily opened. and registering a call at the central station. The circ-uit is noiv in readiness to receive another call from the branch o'ce.

Let iis-assume. that the lineshoivn on the drawing is busy, being operated from another line plug, such as line plug` No. 2. The operator in front of line plug llo. l is handed a message to be transmitted to this branch ofice, which is busy, and she must be able to test the line for busy before sending the message. The operation ot the operators cord circuit is as follows: A

The idle condition of the cord circuit is shown on the drawing. All of the relays ar nnoperated, and the line from the. printer is open. 'The operator plugs her jack on to the line plug of the line Wanted, connecting the tip to` line and grounding the extra contact. Inasmuch as this line is busy, the signaling battery of positive polarity as been removed from the line and there` will be operating battery of negative potential on the plugs associa-ted with this line at each of the "turrets This negative potential will be applied to the plate of the vacuum tube, but since this negative potentialwill not cause a iiow of plate current, relay D Will not operate, `and consequently, neither E nor F.

'lhus it will be seen that even though an operator plugs in on a busy line andl does not remove her plug immediately, her printer' cannot be connectedto this line as long as the is busy. En,rt-herrnore,v because of the impedance of the vacuuintube plate ings circuit, there lis-no interference with the printer sienals then passing over this line.

A busy lamp 17 connected to aback contact of relay yE and receiving its ground from the extra cont-act ot the jack, will` light when the jack is connected to a busy line and will remain lighted until the jack is removed or the line becomes idle.`

Relay G shown at the branch oftice is not an essential part of the circuit and has merely been included as a suggested method ot permit-ting the Vcentral otlice operator to call the branch otlice. A bell or `lamp may be connected to the contacts of relay Gr in such a manner as to allow the general oilice operator to actuate the bell or light the lamp by depressing a key or keys on her printer thus causing the armature of relay G to move back and forth. f

lY e claim 85 l. ln coinbinatioina plurality ot transmitting and receiving telegraphapparatus at branch oiiices with lines terminating in multiple single-contact line plugs at a cen ral station, means for normally applying signalQO battery to each line, means responsive to interruption of the line at a branch ohce to display a call signal at the central station, transmitting and recording telegraph apparatus at the central station including a source A@ ot operating battery, and acord circuit for the central stationapparatus including means responsive to signal battery for connecting said apparatus and operating battery to the line. f

In combination, a plurality of transmitting and receiving telegraph apparatus at branch otlices with lines terminating in multiple single-contact line plugs at a centralv station, means for normally applying signal' 105 battery to each line, means responsive to incrruption ot the line at a branch oiiice to disjpiay a call signal at the central station, transmitting and recording telegraph apparatus at the central stat-ion including a source ot op-Z 110 erating battery, a cord circuit forthe central station apparatus including means responsive to signal battery for connecting said apparatus and operating battery to the line, and means responsive to the application of oper-$ ating battery to the line to disconnect the signal battery from the line.

3. In combination, a plurality of transmitting and receivingI telegraph apparatus at branch offices` with lines terminating in mul-2 120 tiple single-contact line plugs at a central station,1neans for normally applying signal battery to each line, means responsive to interruption of the line. at a branch oliice to, display a call signalat the central station, trans-c apparatus and operating battery to the line, and to simultaneously display a busy signal and extinguish the call signal.

4. In combination, a printer at a branch station and a line connecting the branch station to multiple single-contact plugs at a central station, means at the central station for normally applying signal battery to the line, said line. circuit being normally completed at said branch station, a relay at the central station in circuit with said signal battery and responsive to interruption of the line at the branch station to' display a call signal, a `Jrinter at the central station and a cord circuit therefor including a source of operating battery, and means responsive to operating battery on the line to disconnect saidrelay and said signalbattery from the line.

5. In combination, a printer at a branch station and a line connecting the branch station to multiple single-contact line plugs at a central station, means at the central station for normally applying signal battery7 to the line, said line rcircuit being normally completed at said branch station, means at the central station responsive to interruption of the line at the branch station to display a call signal, a printer at the central station and a cord circuit therefor including a source of operating battery, and means responsive to operating battery on the line to disconnect the signal battery and to simultaneously display a busy signal and extinguish the call signal.

6. In combination, a plurality of transmitting and receiving telegraph apparatus at branch oiiices with lines terminating in multiple single-contact line plugs at a central station, means at the Central station for normally applying positive battery to each line, and a plurality of printers at the central station each provided with a cord circuit, each cord circuit including means responsive to positive current only from said line to connect the printer to the lines, and whereby when a cord circuit is connected to a line having negative or no battery thereon, the printer of that cord circuitis not connected to said line.

7.V In combination, a plurality of transmitting and receiving telegraph apparatus at branch oiiices with lines terminating in multi-r ple line plugs at a central station, means at the central station for normally applying positive battery to each line, and a plurality of printers at the central station each provided with a cord circuit, each cord circuit including uni-directional conductive means responsive to positive current only from said line to connect the printer to the line, and whereby when a cord circuit is connected to a line having negative or no battery thereon, the printer oi that cord circuit is not connected to said line and does not interfere With the operation of the line.

8. A cord circuit for simplex printers com- Vprising, in combination With the printer, a

jack adapted to connect to multiple line plugs, a circuit connecting thejack and printer including a normally open contact, and means included in the circuit between said jack and" prising, in combination with the printer, af

jack adapted to connect to multiple line plugs, a circuit connecting the jack and printer including a normally open contact, means included in the circuit between said jack and printer, responsive only to positive currentIN from said line, to close said normally open contact and testing means connected to said jack Which gives a busy line signal when the operator connects the jack to a busy line pluo.

10. A cord circuit for simpleX printers com- 'a5 prising, in combination with the printer, a jack adapted to connect to multiple line plugs, a circuit connecting the jack and the printer including a normally open contact, and unidirectional conductive means connected to'O said jack, responsive only to positive current from said line, to close said normally open contact.

11. In combination, a printer line terminatp ing at a central station, a relay in said liner( provided with a holding circuit, a second relay controlled by the first relay and having a holding circuit, a call signal and a busy line signal controlled by said second relay, and means for periodically opening the holding circuit of both said relays.

12. In combination, a printer line terminating at a central station, a relay in said line provided with a holding circuit, a second relay controlled by the iirst relay, a call signal and a busy line signal controlled by said second relay, and means for periodically opening the holding circuit of said relay.

13. In combination, a printer line terminat-V ing at a central station, a relay in said line, a second relay controlled by said first relay and having a holding circuit, a call signal and a busy line signal controlled by said second relay, and means for periodically open-I ing said holding circuit.

14. In combination, a plurality of transmitting and receiving telegraph apparatus at branch oiiices With lines terminating in multiple single contact line plugs at a central station, means kfor normally applying signal battery to each line, means for displaying at the central otlice a signal in response to a signaling condition from the branch office, transmitting and recording telegraph apparatus at the central station including a source of operating battery, and a cord circuit for the central station apparatus including means responsive to signal battery for connecting said apparatus and operating battery to the line.

tures.

In testimony whereof We aix our signa- HERBERT W. BRAKE.

WILLIAM B. BLANToN. 

